From owner-freebsd-hackers@FreeBSD.ORG  Thu May  6 00:57:28 2004
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 1ACD716A4CE
	for <freebsd-hackers@freebsd.org>;
	Thu,  6 May 2004 00:57:28 -0700 (PDT)
Received: from fbsd.lv (fbsd.lv [159.148.95.82])
	by mx1.FreeBSD.org (Postfix) with ESMTP id C0D0E43D39
	for <freebsd-hackers@freebsd.org>;
	Thu,  6 May 2004 00:57:27 -0700 (PDT)	(envelope-from artis@fbsd.lv)
Received: by fbsd.lv (Postfix, from userid 10000)
	id D9D44C12A; Thu,  6 May 2004 10:57:25 +0300 (EEST)
Date: Thu, 6 May 2004 10:57:25 +0300
From: Artis Caune <artis-ml@fbsd.lv>
To: freebsd-hackers@freebsd.org
Message-ID: <20040506075725.GA1056@fbsd.lv>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Subject: ioctl
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 06 May 2004 07:57:28 -0000

Is it correct to use code like this
instead of copyin() / copyout() ?
Kernel module gets pointer to structure
which resides in userland memory space
and modify it directly!!!
   > userland: ioctl(tp_fd, TP_GET_TP_STATS, &tp_stats)
   > kernel:   tp_stats->hooked = hooked;
(freebsd 5.x, KLD)


-----   START userland   -----

#define TP_GET_TP_STATS _IOR('D', 200, struct tp_stats_s)

struct tp_stats_s {
	int hooked;
	u_short policer_active_pipes;
} tp_stats;

if (ioctl(tp_fd, TP_GET_TP_STATS, &tp_stats) != -1) {

    printf("Traffic Policer is %s\n",
           tp_stats.hooked ? "enabled" : "disabled");
    printf("statistics:\n");
    printf("  %-30s%u\n", "pipes hash table depth",
           tp_stats.policer_pipes_hash_depth);
    printf("  %-30s%u\n", "active pipes",
           tp_stats.policer_active_pipes);
  } else
    fprintf(stderr, "IOCTL error\n");

-----   END userland   -----



-----   START kernel   -----

static int
tp_dev_ioctl (dev_t dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
{
  switch (cmd) {
  case TP_GET_TP_STATS:
    err = get_tp_stats((struct tp_stats_s *)addr);
    break;
...
}

static int
get_tp_stats (struct tp_stats_s *tp_stats)
{
  TP_LOCK;
  tp_stats->hooked = hooked;
  /* hash depth will be gone in -release, just for debug */
  tp_stats->policer_pipes_hash_depth = policer_pipes_hash_depth;
  tp_stats->policer_active_pipes = policer_get_active_pipes();
  TP_UNLOCK;

  return (0);
}
...
-----   END kernel   -----



thanks,

-- 
Artis